Polarization Formula: Polarization of Waves and Examples

Polarization formula is calculated by considering the waveform of physical phenomena such as light or electromagnetism. In case of electromagnetism polarization refers to the direction of electric flux lines in an electromagnetic field. And in case of light waves Waves with the same direction of vibration for all waves.

• Polarization differs between transverse and longitudinal waves.
• Polarization depends on the refractive index (µ) of a material.
• The degree of polarization is dependent on the material and the angle at which the light is reflected.

Read More: Coherent and Incoherent Addition of Waves

Key Terms: Polarization, Electromagnetic Wave, Light Wave, Polarized light, Transverse wave.

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What is Polarization?

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Polarization is a property of transverse waves determining the direction of wave oscillations which is perpendicular to the direction of wave motion. Such polarization property is also observed in electromagnetic waves as they have wave nature too. For optics, polarization is the property in which the light waves are vibrating along a single plane.

• Polarization is observed in transverse waves, in which all points on a wave oscillate along the right angle to the wave motion.
• The process of transforming unpolarized light into polarized light is called polarization.
• An unpolarized light can be polarized by Transmission, Reflection, Refraction and Scattering.
• In sunglasses, 3D movies and infrared spectroscopy polarization of light is used.

Read More: Wave Optics

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Polarization of Waves

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The vibration direction of the lighting material is the cause of light polarization. Natural light is uniform wave vibrations in all directions. As a result, natural light lacks polarization and is classified as a non-polarized Electromagnetic wave. 

• The electric field's force lines are perpendicular to the magnetic field's.
• The polarization of an electromagnetic wave is determined by the direction of the electric field.
• There are two types of polarization – linear and circular polarization.
• In linear polarization waves can be thought of as vibrating in one plane.
• In circular polarization with each cycle of energy, electric lines of force rotate 360 degrees.
• There’s one more kind of polarization called elliptical polarization, a mixture of both linear and vertical polarization.

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Formula of Polarization

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The formula of polarization can be derived from the law of Brewster’s angle. This law establishes that the maximum polarization of a light ray can be obtained by allowing that ray to fall on a transparent material surface so that the refracted ray forms a 90° angle with the reflected ray. Brewster’s law is used in modern lasers to make the reflections at the laser cavity's mirror surfaces produce linearly polarized light.

• Brewster’s angle can be expressed as the tangent inverse form of the ratio between initial and final medium’s refractive index.
• It neither has any unit nor has any dimension.
• The angle is denoted by the symbol “θ”.

The mathematical form of the equation will be– tan θ = n₂/n₁

Here, θ is the Brewster’s angle, n₁ is the refractive index of media 1 and n₂ is the refractive index of media 2.

Formula of Polarization

Read More: Huygens Principle

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Things to Remember

• Polarization is a transverse wave feature that determines the direction of wave oscillations that is perpendicular to the direction of wave motion.
• Transforming unpolarized light into polarized light is called polarization.
• The electric field's force lines are perpendicular to the magnetic field's.
• There are two types of polarization – linear and circular polarization.
• Brewster’s angle can be expressed as the tangent inverse form of the ratio between initial and final medium’s refractive index.
• The mathematical form of polarization formula is– tan θ = n₂/n₁. Here, θ is the Brewster’s angle, n1 is the refractive index of media 1 and n₂ is the refractive index of media 2.